The present invention relates to an air intake apparatus for an internal combustion engine, and in particular, to an air intake apparatus for an internal combustion engine containing a rotation force transmission structure for an opening and closing valve of an air intake apparatus.
Similar techniques are described in Japanese application patent laid-open publication No. Sho 60-224924, Japanese application patent laid-open publication No. Hei 6-81719, Japanese application patent laid-open publication No. Hei 6-81735, and Japanese application patent laid-open publication No. Hei 8-170536, etc.
In a construction shown in FIG. 2 of Japanese application patent laid-open publication No. Sho 60-224924, by rotating a substantially cylindrically shaped surge tank, a position of an opening portion of an air intake conduit is varied, and when a length of the air intake conduit is varied, an output torque of an internal combustion engine can be heightened by utilizing an air intake inertia effect.
In a construction shown in FIG. 33 of Japanese application patent laid-open publication No. Hei 6-81719 or in a construction shown in FIG. 3 of Japanese application patent laid-open publication No. Hei 6-81735, an opening and closing valve is provided at a midway point of an air intake conduit. When an internal combustion engine rotates at a low speed rotation, by closing the opening and closing valve, a length of the air intake conduit is made long, and an output torque during the low speed rotation of the internal combustion engine is heightened.
In a construction shown in Japanese application patent laid-open publication No. Hei 8-170536, two air intake conduits having different lengths are shown. At an air intake passage of an intermediate portion of the shorter air intake conduit, a cylindrical shape shielding mechanism is provided. In response to a rotation number of an internal combustion engine, the shielding mechanism is opened or closed, and by employing only the other longer air intake conduit or by employing both air intake conduits, an increase in a flow passage cross-sectional area is selected, as a result an output torque of the internal combustion engine is heightened.
In each of the above stated prior arts, the aim is to heighten the output torque utilizing the inertia effect of the intake air in the internal combustion engine. The length of the air intake conduit or the flow passage cross-sectional area is varied. To vary the length of the air intake conduit or to vary the flow passage cross-section area, a butterfly shaped valve or a cylindrical shaped opening and closing valve is used.
The butterfly shape valve comprises a flat plate shaped valve main body and a rotating shaft, and the valve main body and the rotating shaft are manufactured separately or independently. This valve main body and this rotating shaft are combined with screw members etc. The rotating shaft has a long and slender rod shape. To this rotating shaft plural butterfly shaped valves are installed. To prevent an obstruction of a rotation sliding operation due to a bending deformation of the rotating shaft, not only is a bearing member provided to both ends of the rotating shaft, but also, a bearing member is provided between the butterfly shape valve and another butterfly shaped valve.
When installing the above stated assembly with the valve main body and the bearing members at a midway point of the air intake conduit an, where the air intake conduit is formed by two-divisional construction or two separated parts, there is a fear of lowering the dimensional accuracy of the air intake apparatus during assembly.
On the other hand, in the cylindrical shaped opening and closing valve in the air intake apparatus for the internal combustion engine, an opening portion which penetrates in a radial direction is provided on the cylindrical shaped opening and closing valve. A valve portion is constituted by the opening portion and another portion. By rotating this opening portion, the intake air, which passes through the opening portion, is discontinued.
With the above stated mechanism, a whole peripheral portion of the cylinder of the internal combustion engine becomes a rotating shaft. A bending deformation of the rotating shaft in the cylindrical shaped opening and closing valve is smaller than that of the rotating shaft of the butterfly shaped valve. Since a shaft portion and the valve portion are manufactured integrally, the manufacturing is easier.
Further, by employing an assembling method in which a hole portion for inserting the cylindrical shaped opening and closing valve is manufactured integrally in an axial direction with a part of the air intake conduit of the air intake apparatus for the internal combustion engine, and the cylindrical shaped opening and closing valve is inserted in to this hole portion, it is unnecessary to divide two parts, such as the air intake conduit in the case of the butterfly shape valve. A accordingly a lowering in a dimensional accuracy of the air intake apparatus for the internal combustion engine in a radial direction, which is accompanied by the assembling work, can be avoided.
In a construction of the air intake apparatus for the internal combustion engine shown in Japanese application patent laid-open publication No. Hei 8-170536, one end of a cylindrical shaped opening and closing valve is contacted to a small hole portion which is provided at a bottom of a hole portion, and also, using a spring member, the cylindrical shaped opening and closing valve is added with an axial direction force to come off from this small hole portion of the cylindrical shape opening and closing valve.
However, in the above stated prior arts, there is no consideration about a relationship between a direction of the rotating shaft of the connection member and a direction of the rotating shaft of the cylindrical shaped opening and closing valve. As a result, since a divergence exists, there is a possibility the rotation may become rough.
The inventors of the present invention have filed a prior patent application about an air intake apparatus for an internal combustion engine in which the problems not solved in the above stated prior arts can be solved (at the present patent filing time, the above stated prior patent application is not laid-opened and does not form the prior art against the present patent application). Namely, in the prior patent application, the connection member for the cylindrical shaped opening and closing valve and the rotating mechanism is contacted to the cylindrical shaped opening and closing valve through a ball like member.
Even if the inclination (the divergence) exists between the direction of the rotating shaft of the connection member for connecting the rotating mechanism and the direction of the rotating shaft of the cylindrical shape opening and closing valve, since the ball like member works as one kind of a ball joint mechanism, the rotation can be transmitted smoothly.